1. Field of the Invention
The present invention relates to a display apparatus that is favorably used in a display system that displays on a liquid crystal element or the like color signals such as R, G, B signals output from a PC.
2. Description of the Related Art
In a conventional display system in which color signals such as R (red), G (green), and B (blue) signals generated by a personal computer (PC) are transmitted to a display apparatus via a cable, there are many cases in which the display apparatus is located at a considerable distance from the PC, resulting in a long cable needing to be used. If the signal transmission distance is lengthened like this, the problem arises of phase differences being generated between the R, G, B signals.
In particular, in the case of a high resolution display apparatus that uses a liquid crystal display element, even if there is only a slight discrepancy between the phases of the R, G, and B signals, failures sometimes occur such as portions of the ends of displayed characters becoming colored. In some modern systems there are even cases when the PC and the display apparatus may be located as much as 300 meters away from each other, so that the above problem of the phase difference generation becomes an extremely serious one.
In order to solve this problem a method has been employed in which the phases are manually adjusted for each of the R, G, B signals.
However, in the method of adjusting the phases for each of the R, G, B signals, if, for example, a phase is delayed, there are cases in which a large phase correction of close to one cycle of the horizontal synchronization signals is necessary. Therefore, not only does the adjustment take time, but the further problem of an increased circuitry size arises. In addition, in the case of a multi-sync display apparatus in which a plurality of types of R, G, B signals each having different synchronization signals are selectively input, because the phase difference that needs to be corrected is different for each type of input signal, the problem arises that manual adjustment must be performed again every time the type of input signal changes.
The present invention was conceived in order to solve the above described problems, and it is an object thereof to provide a display apparatus capable of reducing a phase adjustment amount and automatically achieving a phase adjustment in a short time using a simple circuit structure.